1. Field of the Invention
The present invention generally relates to an optical interface device for extracting, inserting and passing light transmitted bi-directionally on a fiber optic line, and more particularly to such an optical interface device for use as a fundamental element of a non-blocking, bidirectional, multi-channel, protocol independent transmission medium for the simultaneous transfer of digital, analog, and discrete data.
2. Background Discussion
A variety of different topologies are employed to manage the transmission of data over a network. Known network topologies include: 1) broadcast, such as utilized on a data bus; 2) point-to-point repeater link, such as seen with the ring configuration; 3) and logical star, where all data is transmitted to a central location for retransmission to an intended recipient.
One particular problem with these known network topologies is that they cannot be easily integrated with one another. In essence, once a particular topology is chosen for managing the transmission and receipt of data on a given network, that topology must always be used by the network. This lack of adaptability is a particular detrimental problem when new or more useful topologies are developed but cannot be applied to existing data transmission networks which are locked into archaic, less efficient topologies.
Recent advances in data transmission technology have been directed to increasing the bandwidth or data capacity of the network, i.e., increasing the amount of data that can be transmitted by the network.
Physics imposes data rates limits on standard optical networks which encode data in pulses of laser light and dispatch them through wires made of glass. Very fast data rates require very short pulses, which tend to smear into one another as they travel through kilometers of fiber. Electronic devices staggered along the path can clean up the signal, but they are expensive and can work on at most 50 billion bits per second.
To go faster, researchers have transmitted many signals simultaneously over a single fiber by encoding them in different wavelengths or channels. Devices that use this technique, known as wavelength division multiplexing (WDM) have boosted the capacity of existing fiber twenty fold.